You can travel to other countries in Schengen area (which includes Germany) and stay there for up to 3 months. You're allowed to perform work activities requested by your Finnish employer as long as you're not employed by an entity in Germany and as long as your salary is being paid by your Finnish employer. I see no problem here.

I highly doubt Migri would consider this as grounds for faster application process. Having that said, you can still try if you feel like it.

Every f*cking case is unique. You can't measure the result of your application based on arbitrary anecdotes online. Stop being a moron!

You can travel to other countries in Schengen area (which includes Germany) and stay there for up to 3 months. You're allowed to perform work activities requested by your Finnish employer ...

Thanks for your reply.

This is a response I'm quoting from the German embassy in Finland:

even though your colleague will be doing his work for the Finnish Company and not a German Company it is classified as work according to German law. As he is not staying that long he will not need a work permit, but as a third-country-national he needs to apply for a visa, because of work. His Finnish residence permit gives him the opportunity to travel within the EU for 90 days within a period of time of 180 days, but as soon as somebody wants to work in Germany this kind of residence permit is not valid also for working in another EU country.

So you need to apply for a work permit in Germany or become a Finn fast.
Therefore Migri has to speed up its process to avoid a permit process in Germany.
I have the feeling they will not be impressed.